1. Field of the Invention
The present invention relates to air conditioning and heating systems, and more specifically to an access door for a furnace, heat pump, air conditioner, or other type of air handler.
2. Description of Related Art
Air conditioning systems typically include an air-handler that provides conditioned air to a comfort zone, such as a room or a designated area within a building. The conditioning of the air may include, but not be limited to heating, cooling, humidifying, dehumidifying, filtering, ventilating, and their various combinations. Air handlers often include a sheet metal enclosure that contains various components, such as a blower, filter, heat exchanger, controls, etc.
When repairing or otherwise servicing an air handler, a hinged door or a removable panel covering an opening in the enclosure can provide access to the various components inside. A hinged door can be easy to use, as it usually takes less dexterity to open and close. A hinged door does not need to be manually realigned to the access opening whenever the door is operated, so a hinged door can be opened and closed quickly. Examples of a hinged door can be found in U. S. Pat. Nos. 4,095,646; 4,292,815; 4,325,594 and 4,333,206.
Sometimes, however, a hinged door may get in the way when doing extensive servicing, such as replacing a blower. In such cases, a removable panel may be preferred, such as the one disclosed in U.S. Pat. 4,776,484. However, a removable panel can be a nuisance to frequently remove and reinstall for minor servicing, such as replacing an air filter.
To overcome the limitations of current air handler enclosures, it is an object of the invention to provide a door panel that can pivot between open and closed positions and be prevented from disengaging the enclosure when the panel is fully open or closed.
Another object is to provide a pivotal door panel with an intermediate open position where the panel can be completely disengaged from the enclosure.
Another object is to provide a door panel that can pivot open and closed for replacing an air filter, and can be selectively engaged and disengaged from the enclosure for replacing a blower.
A further object is to distribute the weight of a pivotal door panel across a full line of pivoting contact between the panel and the enclosure, thereby reducing contact wear or at least distributing the wear more broadly than if the contact were concentrated at just a few relatively narrow hinges.
A still further object is to use the weight of the panel itself to urge engagement between the panel and the enclosure as the panel pivots through a range of intermediate positions between its fully open and closed positions. This helps prevent the panel from disengaging the enclosure unintentionally.
Yet another object of the invention is to use a relatively short catch in combination with a significantly longer flange underneath the access opening to releasably capture a lip extending from the door panel.
Another object of the invention is to use sheet metal of a substantially uniform thickness to make at least one of the catch, flange, and lip, thereby simplifying the manufacturing process of making the parts.
Another object of the invention is to place the flange along a generally vertical plane to increase the flange""s ability to support the weight of the door panel.
Another object of the invention is to provide the door panel with a sheet metal lip having surfaces that are spaced apart and on opposite sides of the sheet metal, wherein one surface keeps the panel and enclosure engaged when the panel is fully open, and the other surface keeps the panel and enclosure engaged when the panel is fully closed, whereby the wear and load is applied alternately to the two surfaces.
Still another object of the invention is to place the two surfaces perpendicular to the direction that the panel would tend to move if the panel were pulled directly away from the enclosure""s opening.
These and other objects of the invention are provided by an air handler enclosure having a pivotal door panel that covers an access opening leading to a blower inside the enclosure. The door panel is held in engagement with the enclosure when the panel is fully open or closed. The panel can completely disengage the enclosure if the panel is first pivoted to an intermediate position between the fully open and fully closed positions.